RESUMO

While physical activity and zinc supplementation have shown benefits in diabetes management, little is known about their effect on less severe glucose homeostasis disorders, such as impaired glucose tolerance. On the other hand, sirtuins have an important role in glucose metabolism and insulin sensitivity, but to date, there is no information about the impact of zinc supplementation or physical activity on their regulation in individuals with impaired glucose homeostasis. The aim of this study was to assess the effect of supplemental zinc, muscle-resistance training, and their combination on the expression of selected sirtuins in insulin-sensitive tissues of rats with impaired glucose tolerance. Thirty male Wistar rats with impaired glucose tolerance were fed a high-fat diet for 12 weeks while subjected to zinc supplementation, resistance training, both, or none. Morphometric and metabolic evaluations were performed at the end of the experimental period, and gene expression of sirtuins 1, 2, 4, and 7 was assessed in liver, gastrocnemius muscle, and white adipose tissue. Results showed that zinc supplementation and/or resistance training did not improve metabolic parameters of rats with impaired glucose tolerance, nor did they affect the expression of selected sirtuins in any of the tissues evaluated. However, the expression of some sirtuins was associated with metabolic parameters in a tissue-specific manner. Additional studies are needed to evaluate whether zinc supplementation and/or resistance training can improve metabolic status or modulate sirtuins expression in advanced stages of impaired glucose homeostasis.

RESUMO

The levels of amylase, maltase, lipase and alkaline protease from eight fish species of the Amazon were analysed. The enzyme levels are not related to fish feeding habits, reflecting their ever-changing habitats and their opportunistic feeding behaviour.

Assuntos

RESUMO

Prolactin (PRL) is a pituitary hormone that plays important roles in mammalian reproductive physiology, specially lactation. The regulation of PRL secretion shows important species differences. To study PRL regulation in a subhuman primate, the Cebus apella, we developed an heterologous radioimmunoassay using an antibody against rhesus PRL (anti-m5PRL) and a Cebus apella pituitary extract as PRL standard. The assay has a sensitivity that allows measurements of cebus PRL in small amounts of Cebus apella plasma obtained from animals in different physiological conditions. Plasma cebus PRL concentrations (+/-SEM) varied in different reproductive stages. PRL concentration in adult Cebus apella females that have regular menstrual cycles (161.6 +/- 15.0 mIU/ml) was similar to that found in adult (100.3 +/- 7.6 mIU/ml) and prepuberal males (101.2 +/- 3.9 mIU/ml). PRL concentration was higher in pregnant (677.8 +/- 11.8 mIU/ml) and in nursing (625.0 +/- 47.0 mIU/ml) Cebus apella females than in 15-d post-partum non-nursing (369.0 +/- 19.0 mIU/ml) and cycling females. PRL concentration in Cebus apella newborns (719.0 +/- 49.2 mIU/ ml) was similar to that found in pregnant and nursing females, and higher than in the other females as well as adult and prepuberal males. These differences in PRL concentration in different physiological conditions are similar to that observed in humans and other primates. A PRL response to thyrotropin releasing hormone (TRH) was demonstrated in 2 nursing Cebus apella females, similar to the response found in nursing woman and rhesus. Altogether, the data presented support the proposal that the assay developed to measure PRL in Cebus apella is an adequate tool to study the physiology of PRL in this species.

Assuntos

RESUMO

Prolactin (PRL) is a pituitary hormone that plays important roles in mammalian reproductive physiology, specially lactation. The regulation of PRL secretion shows important species differences. To study PRL regulation in a subhuman primate, the Cebus apella, we developed an heterologous radioimmunoassay using an antibody against rhesus PRL (anti-m5PRL) and a Cebus apella pituitary extract as PRL standard. The assay has a sensitivity that allows measurements of cebus PRL in small amounts of Cebus apella plasma obtained from animals in different physiological conditions. Plasma cebus PRL concentrations (+/-SEM) varied in different reproductive stages. PRL concentration in adult Cebus apella females that have regular menstrual cycles (161.6 +/- 15.0 mIU/ml) was similar to that found in adult (100.3 +/- 7.6 mIU/ml) and prepuberal males (101.2 +/- 3.9 mIU/ml). PRL concentration was higher in pregnant (677.8 +/- 11.8 mIU/ml) and in nursing (625.0 +/- 47.0 mIU/ml) Cebus apella females than in 15-d post-partum non-nursing (369.0 +/- 19.0 mIU/ml) and cycling females. PRL concentration in Cebus apella newborns (719.0 +/- 49.2 mIU/ ml) was similar to that found in pregnant and nursing females, and higher than in the other females as well as adult and prepuberal males. These differences in PRL concentration in different physiological conditions are similar to that observed in humans and other primates. A PRL response to thyrotropin releasing hormone (TRH) was demonstrated in 2 nursing Cebus apella females, similar to the response found in nursing woman and rhesus. Altogether, the data presented support the proposal that the assay developed to measure PRL in Cebus apella is an adequate tool to study the physiology of PRL in this species

Assuntos